An Electro-Hydraulic Manifold Assembly And Method Of Making Same For Controlling De-Activation Of Combustion Chamber Valves In A Multi-Cylinder Engine.
The present invention relates to an electrically operated valve and manifold assembly for controlling flow of hydraulic fluid in a circuit for deactivating the hydraulic lash adjusters or valve lifters in an internal combustion engine. In certain multi-cylinder motor vehicle engine applications, it has been desired to deactivate the combustion chamber valves of the engine for purposes of disabling combustion in certain of the cylinders during light load or xe2x80x9clow throttlexe2x80x9d applications in order to increase efficiency, conserve fuel and reduce the emissions from the engine combustion chambers. It has also been found that disabling the operation of some of the cylinders enables the remaining cylinders to operate at a higher throttle or load condition which reduces the air flow or xe2x80x9cpumpingxe2x80x9d losses which would otherwise occur over a nearly closed air throttle.
Where the engine valves are operated from a camshaft, such as by hydraulic valve lifters or lash adjusters through direct action for overhead cam arrangements or through intermediate linkages such as rocker arms, finger followers or push rods or other types of engine valve gear arrangements, the valves may be left close by hydraulically disabling the valve lift function.
In such arrangements, an electrically operated valve opens a flow of hydraulic fluid, typically engine lubricant, through a separate channel or circuit to cause hydraulic movement of the lash adjusters to a position preventing movement of the engine valves.
In engines where such valve de-actuation is employed, in order to simplify the final assembly of the engine and installation of the electric valves for de-actuating the valve lifters, it has been desired to provide an assembly of a manifold and the valves for deactivating respectively the desired cylinder which may be mounted as a unit on the engine during engine buildup. Heretofore, such an arrangement has required two separate manifold plates usually cast of aluminum material with subsequently machined surfaces formed on the castings in order to provide the appropriate passages for valving the lubricant to the valve lifters and to provide a mounting arrangement for the individual electric valves to connect to the respective hydraulic circuit and to facilitate the manifold and valve assembly as a unit onto the engine.
Such a known arrangement is shown in FIG. 4 wherein the valve and manifold assembly indicated generally at 1 includes an upper manifold plate or deck 2 having a channel 3 formed therein which communicates through an aperture 4 in a gasket 5 disposed over the undersurface of the deck 2. Gasket aperture 4 communicates with an inlet port 6 provided in a lower manifold plate or deck 7 which is adapted for connecting to an hydraulic circuit on the engine block (not shown). Channel 3 communicates through a second aperture 8 formed in the gasket 5 which aperture 8 communicates with a valving chamber 9 having an electrically operated valve 10 mounted on the lower deck 7 for valving flow from channel 3 to a channel 11 which supplies an outlet port (not shown) for the respective valve to be de-actuated.
In operation, pressurized fluid is provided in a supply channel 3 formed in the undersurface of upper deck 2 through inlet port 6 in the lower deck; and, the supply channel communicates through an aperture 8 in the gasket to valving chamber 9. Upon energization, solenoid 10 effects movement of a valve member 13 from its valve seat and permits flow through the gasket aperture 12 which communicates with outlet channel 11 formed in the undersurface of the upper deck 2. Channel 11 communicates with respective control pressure port apertures in the gasket (not shown) for de-actuating the respective engine valves and also communicates through a flow limiting bypass gasket port 17 and bypass orifice 16.
A bleed orifice 16 is provided in the lower deck 7; and, orifice 16 communicates with a bypass aperture 17 in gasket 5 which communicates with the supply channel 11 to provide a highly restricted and limited bleed flow to bypass the valve and return to an unshown sump. An electrical lead frame 9 is provided for electrical connection to the solenoid 10.
The known arrangement shown in FIG. 4 has thus required two separately machined manifold decks or plates and has proven to be prohibitively costly and heavy for high volume production motor vehicle applications.
Thus, it has been desired to provide a way or means of reducing the weight and cost of the electric valve and hydraulic manifold assembly for controlling the de-actuation of the combustion chamber valves in a multi-cylinder motor vehicle engine.
The present invention provides a solution to the above-described problem and employs an electric valve and manifold assembly having an upper manifold plate with lubricant or hydraulic fluid passages therein which has disposed over the underside thereof, with ports formed therein for communicating with the corresponding fluid passages and a gasket which has formed integrally thereon mounting surfaces forming a valving chamber with the manifold deck and providing valve mounting cavities. Electrically operated valves are mounted directly on the gasket mounting cavities; and, the gasket is retained by a simple flat plate and the valves retained on the gasket mounting cavities by a stamped bracket which is attached through the gasket to the manifold deck. The assembly of the present invention thus eliminates the need for a separate secondary or lower manifold deck having machined hydraulic passages therein. The present invention reduces the overall cost and weight of the manifold assembly and simplifies the fabrication thereof yet preserves the function of attaching a single unit to an engine for effecting electrically controlled deactivation of the engine valve lifters.